Apparatus for preparing ampullas

Abstract

The invention relates to an apparatus for measuring the concentration of gaseous hydrogen dissolved in a liquid substance. The apparatus comprises an electrochemical cell constituted of a polymeric membrane in contact with a sample of the liquid substance and which is permeable to hydrogen, of an electrolyte capable of causing an oxydation reaction of the hydrogen diffused through the polymeric membrane, at a first electrode, and a reduction reaction of an oxygenated gas at a second electrode, so as to deliver an electric current proportional to the hydrogen concentration to be measured. An electrovalve operates, when activated, to exhaust the liquid substance sample at a predetermined instant in the measuring process. Moreover, the circuit amplifies a voltage corresponding to the value of the current proportional to the concentration, which current flows through a load resistance mounted in parallel across the first and second electrodes and the input of the amplifying circuit. A display device is connected to the output of the amplifying circuit and supplies a digital measure of the hydrogen concentration in the liquid substance. A control unit determines the operation times of the electrochemical cell, of the electrovalve as well as of the digital display device pursuant to a predetermined sequence.

We claim: 
     
       1. An apparatus for preparing ampullas useful in the calibration of a means for detecting and measuring the hydrogen gas content in a liquid substance, said apparatus comprising: an elongated glass tube having a closed extremity and an open extremity, and provided with a plurality of conduits disposed along a generatrix of said tube;   a plurality of ampullas, each ampulla having approximately half of its volume filled with a liquid identical to said liquid substance and being hermetically connected to said tube conduits;   a vacuum pump means for degasifying the liquid contained in the ampullas;   a reservoir containing a nitrogen-hydrogen mixture in a proportion of about 1 to 3% vol./vol. for saturating, in the liquid in each ampulla, a given quantity of gaseous hydrogen; and   a three way valve means, secured to said open extremity of the tube, for selectively placing said tube in communication with either said pump means or said reservoir.   
     
     
       2. A apparatus as claimed in claim 1, wherein a rubber band sealingly joins each ampulla to each conduit of said tube. 
     
     
       3. A apparatus as claimed in claim 1, wherein a pressure indicator is connected to said reservoir containing the nitrogen-hydrogen mixture.